What is considered as proof of residence?

On Saturday my daughter and I wanted to go to FNB. We were at the doors at 7:45 to make sure we can go in as they open as we had another appointment at 9:30. My daughter wanted to open a savings account. At 8:00 when the doors opened we were second inline. The information clerk looked at my daughters proof of residence, which was a letter from Unisa confirming her exams for the coming week (the only proof of residence she have as they don't specify what they want as proof of residence when she enquired on required documents) and told my daughter the proof of residence is not adequate. I wanted to know what else they want and she said a utility bill is the only proof of residence they accept.I complained and was told \this is how we work at FNB"I had to go home"